Power management system and fuel cell device

Abstract

We provide a power management system that can reduce the amount of data transmitted. [Solution] The power management system 1 comprises power supply units 10 installed in each of the multiple facilities 2, and a management device 20 that can communicate with the power supply units 10. The management device 20 adjusts the number of power supply units 10 that perform follow operation and the number of power supply units 10 that perform constant operation, and issues output adjustment commands, including output control commands for power supply units 10 that have been determined to perform constant operation and follow operation commands for power supply units 10 that have been determined to perform follow operation. Each of the multiple power supply units is configured to check with the management device 20 at a predetermined first set time interval to see if there is an instruction for the power supply unit 10. The output adjustment command includes a command to cause the management device 20 to check for instructions at a second set time interval, which is shorter than the first set time interval, until a predetermined time has elapsed after receiving the output adjustment command.

Description

Technical Field

[0005]

[0001] The present invention relates to a power management system and a fuel cell device used in the power management system.

Background Art

[0002] Conventionally, the number of facilities such as houses and offices where power supply devices such as power generation devices and charge / discharge devices are installed has been increasing. Such power supply devices and power load devices installed in the facilities are connected to the power grid, and by increasing or decreasing the power at the power reception point of the facility, they are used to adjust the power supply-demand balance in the power grid. In recent years, a virtual power plant (VPP) that remotely controls the power supply devices installed in each facility using IoT devices and functions like a single power plant has become widespread.

[0003] A power management system equipped with a power supply device used as such a VPP communicates via a remote control. By connecting the power management system to a network, various functions can be installed, such as software updates by remote control, reduction of failure rates due to signs of failure, smooth maintenance (reduction of the load on the construction workers performing maintenance) by transmitting and receiving error data, and power transfer between multiple power management systems by VPP. On the other hand, uploading a large amount of data to the server increases the data communication volume, causing an increase in the power consumption of the information collection terminal and an increase in the communication fee between the information collection terminal and the server. Therefore, technologies used in VPP have been studied (for example, Patent Documents 1 and 2).

[0004] Patent Document 1 describes an energy transfer system. In this energy transfer system, in order to calculate the energy balance, the server communicates with the devices of each consumer via a communication device to obtain information regarding energy transfer. At this time, the server and the device communicate so as not to exceed a preset communication capacity within a predetermined period.

[0005] Patent Document 2 describes a power management system. This power management system adjusts the number of power supply units that follow the load power of power load devices (number of load-following units) and the number of power supply units that operate at a constant value instructed by the management device (number of constant-value units). The system is configured to increase the number of constant-value units as the target amount of reverse power flow required to supply power to the power grid increases. Furthermore, based on the amount of reverse power flow that can be supplied from the facility to the power grid in the future, the system prioritizes instructing fuel cell systems with a large amount of reverse power flow capacity to operate at a constant value, thereby minimizing the number of fuel cell systems performing reverse power flow while ensuring that the necessary reverse power flow can be reliably procured from multiple power supply units. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-153450 [Patent Document 2] Japanese Patent Publication No. 2022-155271 [Overview of the project] [Problems that the invention aims to solve]

[0007] Generally, in a VPP, the communication volume increases, especially because communication with the server is frequent. The energy exchange system described in Patent Document 1 restricts communication between the server and the device so as not to exceed a predetermined communication capacity over a set period of time, so it may not be able to respond, for example, when the supply and demand of electricity becomes tight. Also, the power management system described in Patent Document 2 can secure the necessary exchange of power with the minimum number of operating units, but since it is necessary to increase or decrease the constant number of operating units during the controlled period, communication must be performed at a high frequency, and the communication volume increases.

[0008] Therefore, there is a need for a power management system that can reduce the amount of data transmitted, and for a fuel cell device used in such a power management system. [Means for solving the problem]

[0009] The characteristic configuration of the power management system according to the present invention is a power management system comprising power supply devices installed in each of a plurality of facilities, and a management device capable of communicating with the plurality of power supply devices from a remote location outside the facilities, wherein the power supply devices include a power supply unit connected to a power grid and are configured to adjust the output power between an upper limit output power and a lower limit output power, the power load devices installed in the facilities are configured to receive power from at least one of the power supply devices installed in the facilities and the power grid, and the management device determines the number of follow-operating power supply devices, which is the number of power supply devices among the plurality of power supply devices that perform follow-operating operation to adjust their output power to match the load power of the power load devices installed in the same facility, and the number of follow-operating power supply devices, which is the number that perform follow-operating operation to adjust power from the facilities to the power grid. The system adjusts the number of power supply units that perform constant-value operation to set their power output to a predetermined value commanded by the control device, and issues output adjustment commands that include an output control command to determine the output power of the power supply unit that has been decided to perform constant-value operation, and a follow operation command to cause the power supply unit that has been decided to perform follow operation to perform follow operation. Each of the multiple power supply units is configured to check with the control device at a predetermined first set time interval to see if there is an instruction for the power supply unit, and the output adjustment command includes a command to each of the power supply units to check with the control device at a second set time interval that is shorter than the first set time interval, until a predetermined time has elapsed since receiving the output adjustment command.

[0010] With this configuration, in a situation where each of the multiple power supply units is configured to check with the management device at the first set time interval to see if there is an instruction, the system checks for the instruction at the second set time interval until a predetermined time has elapsed after receiving the output adjustment command. Therefore, even if the amount of reverse power flow changes suddenly, for example, the system can reliably procure the correct amount of reverse power flow in accordance with each power supply unit. Furthermore, since the instruction check at the second set time interval is limited to a predetermined time period, the increase in communication volume can be suppressed. Consequently, the power management system reduces the communication frequency after a predetermined time has elapsed after receiving the output adjustment command, making it possible to secure the necessary amount of reverse power flow while reducing the amount of communication.

[0011] Furthermore, it is preferable that the management device determines, based on the amount of reverse power flowable energy that is predicted to be able to be supplied from each of the multiple facilities to the power grid in the future, and the error in the amount of reverse power flowable energy, to be the power supply unit among the multiple power supply units that has the smallest error in the amount of reverse power flowable energy, and to be the power supply unit that performs the constant value operation.

[0012] With this configuration, power supply units with small errors in the predicted reverse power flow capacity can be prioritized and operated at a constant value, thereby enabling the continuous and uninterrupted supply of power from the facility to the power grid.

[0013] Furthermore, it is preferable that the facility is equipped with a prediction device for predicting the amount of power that can be reverse-flowed, and that the management device is configured to receive information about the amount of power that can be reverse-flowed predicted by the prediction devices of each of the multiple facilities.

[0014] With this configuration, the management device can adjust the number of follow-up operating units and the number of constant operating units based on the amount of reverse power flowable predicted by the prediction device, making it possible to appropriately procure the required amount of reverse power flowable power.

[0015] Furthermore, it is preferable that the management device is configured to predict the amount of power that can be reverse-flowed based on the predicted load power of the power load device and the output power of the power supply device, which are received from each of the multiple facilities.

[0016] With this configuration, the management device can adjust the number of follow-up units and the number of constant-operation units based on the predicted amount of reverse power flowable, which is obtained in real time from each of the multiple facilities. This makes it possible to appropriately procure the required amount of reverse power flowable.

[0017] Furthermore, if the error is greater than a preset value, it is preferable for the control device to have each of the multiple power supply units confirm the instruction to the control device at intervals of a third set time, which is shorter than the first set time.

[0018] With this configuration, even if the amount of reverse power flow from a power supply unit suddenly decreases, for example, the amount of reverse power flow from other power supply units can be increased, making it possible to maintain the required amount of reverse power flow.

[0019] Furthermore, when adjusting the number of fixed-value operating units, it is preferable for the management device to determine the number of fixed-value operating units such that the total amount of reverse power flow possible at each of the facilities where the power supply units performing the fixed-value operation are installed is greater than the target reverse power flow amount by a set value.

[0020] With this configuration, for example, even if the amount of reverse power flow from a power supply unit operating at a constant value decreases, the required amount of reverse power flow can be maintained by the amount of reverse power flow from other power supply units.

[0021] Furthermore, it is preferable for the control device to repeatedly issue the output adjustment command.

[0022] With such a configuration, by repeatedly issuing output adjustment commands by the management device, it becomes possible to operate an appropriate number of power supply devices at a constant value operation at all times.

[0023] Further, the fuel cell according to the present invention preferably has the function of the power supply device used in the power management system, and the power supply unit includes a fuel cell unit.

[0024] With such a configuration, a power management system capable of appropriately procuring reverse power flow can be realized by a fuel cell having a fuel cell unit.

Brief Description of Drawings

[0025] [Figure 1] It is a diagram showing the relationship between a facility, a management device, and an aggregation coordinator. [Figure 2] It is a diagram showing a configuration example of a facility. [Figure 3] It is a diagram showing confirmation of an output adjustment command and an instruction. [Figure 4] It is a flowchart showing the processing of the power management system.

Embodiments for Carrying Out the Invention

[0026] <{\alpha} The power management system according to the present invention is configured to be able to reduce the communication volume between a plurality of power supply devices and a management device that manages each of the plurality of power supply devices according to the situation. Hereinafter, the power management system 1 of the present embodiment will be described.

[0027] FIG. 1 is a diagram showing the relationship between a fuel cell device 10 (an example of a "power supply device"), a facility 2 in which a power load device 15 is provided, a management device 20, and an aggregation coordinator 30. FIG. 2 is a diagram showing a configuration example of the facility 2. The power management system 1 includes a fuel cell device 10 installed in each of a plurality of facilities 2 and capable of outputting power, and a management device 20 capable of communicating with the plurality of fuel cell devices 10 from a remote location outside the facility 2. The number of fuel cell devices 10 managed by one management device 20 can be set as appropriate.

[0028] The management device 20, also known as a resource aggregator, is a business that controls the customer-side energy resources, specifically the fuel cell device 10 and the power load device 15, which are customer-side energy resources, to the facility 2 that has entered into a VPP (Virtual Power Plant) service contract. The aggregation coordinator 30 is a business that bundles the amount of electricity controlled by each management device 20 and conducts electricity trading with general transmission and distribution companies and retail electricity companies in the electricity trading market, etc.

[0029] The management device 20 sequentially collects and stores power information from multiple facilities 2, such as the output power of the fuel cell device 10, the load power of the power load device 15, and the power at the point of power reception at facility 2. In this embodiment, when "load power of the power load device 15" is mentioned, it means the total load power of all power load devices 15 installed at facility 2. The management device 20 predicts the power that can be supplied from each facility 2 during a predetermined time period in the future (supplyable power) and transmits the predicted supplyable power to the aggregation coordinator 30. This supplyable power is the adjustment margin, such as the ability to increase or decrease the power at the point of power reception at facility 2. In this embodiment, "increasing the power at the point of power reception" means increasing the power received from the power system 3 to the power line 4, or decreasing the reverse power flow from the power line 4 to the power system 3, and "decreasing the power at the point of power reception" means decreasing the power received from the power system 3 to the power line 4, or increasing the reverse power flow from the power line 4 to the power system 3.

[0030] For example, to increase the power at the point of power reception of facility 2, it is sufficient to either reduce the output power of the fuel cell device 10 or increase the load power of the power load device 15. Therefore, the adjustment margin on the upward side when increasing the power at the point of power reception of facility 2 indicates how much margin is available to reduce the output power of the fuel cell device 10 and how much margin is available to increase the load power of the power load device 15. Also, to decrease the power at the point of power reception of facility 2, it is sufficient to either increase the output power of the fuel cell device 10 or decrease the load power of the power load device 15. Therefore, the adjustment margin on the downward side when decreasing the power at the point of power reception of facility 2 indicates how much margin is available to increase the output power of the fuel cell device 10 and how much margin is available to decrease the load power of the power load device 15.

[0031] Furthermore, the management device 20 determines the baseline power reception point power for the multiple facilities 2 that it manages. This baseline power reception point power corresponds to the sum of the power reception point power of each facility 2, which is predicted to be generated if no adjustment power (i.e., adjustment power provided to transmission and distribution operators and supply power provided to retail operators, etc.) is supplied from each facility 2.

[0032] The aggregation coordinator 30 aggregates the available power received from each control device 20 and conducts power transactions with general transmission and distribution companies and retail electricity companies by bidding in power trading markets such as the supply and demand adjustment market, the wholesale power market, and the capacity market. When the aggregation coordinator 30 receives a supply order for adjustment power, etc., for a predetermined control period in the future from the general transmission and distribution company or retail electricity company with which it has conducted transactions, it distributes and transmits the adjustment power, etc., specified in the supply order to each control device 20.

[0033] When the management device 20 receives a supply order from the aggregation coordinator 30, it distributes and transmits the adjustment power, etc., specified in the supply order to each facility 2. As a result, each facility 2 controls the fuel cell device 10 and power load device 15 as consumer-side energy resources during a predetermined control period in the future, thereby supplying adjustment power, etc., that increases or decreases the power at the power receiving point of facility 2 compared to a case where such control was not performed.

[0034] The fuel cell unit 10 and the power load unit 15 are connected to a power line 4 that is connected to the power grid 3 at facility 2. A power meter 5 for measuring the power at the point of reception of facility 2 is installed on power line 4. Although Figures 1 and 2 show one fuel cell unit 10 installed at facility 2, this is an example, and the number of units installed can be changed as appropriate.

[0035] Information regarding the power at the point of reception, measured by the power meter 5, is transmitted to the management device 20 via the gateway 6 and router 7. For example, information regarding the power at the point of reception is transmitted to the management device 20 at predetermined intervals, such as every 10 seconds.

[0036] The power load device 15 is a variety of devices, such as lighting equipment and air conditioning equipment, and can receive power from at least one of the fuel cell device 10 and the power system 3 installed in facility 2.

[0037] The fuel cell device 10 comprises a fuel cell unit 11 (an example of a "power supply unit") connected to the power grid 3, a power conversion unit 12 that converts the power generated by the fuel cell unit 11 to a predetermined voltage, frequency, and phase and supplies it to the power line 4, and a fuel cell control unit 13 that controls the operation of the fuel cell unit 11 and the power conversion unit 12. The fuel cell device 10 may also include a fuel reformer that generates hydrogen, which is the fuel gas for the fuel cell unit 11.

[0038] In this way, a fuel cell device 10 can be realized that has the functions of a power supply device used in the power management system 1, and the power supply unit includes a fuel cell unit 11.

[0039] The fuel cell control unit 13 can adjust the output power from the fuel cell device 10 to the power line 4 between a predetermined upper limit output power and a predetermined lower limit output power. For example, the fuel cell control unit 13 can maintain the output power of the fuel cell device 10 at the upper limit output power for continuous operation. The fuel cell control unit 13 can also operate the fuel cell device 10 so that its output power follows the load power of the power load device 15. For example, the fuel cell control unit 13 can operate the fuel cell device 10 so that the power measured by the power measurement unit 8 (i.e., the power supplied from the power system 3) is zero or close to zero, thereby causing it to follow the load power of the power load device 15.

[0040] The fuel cell control unit 13 has information about the output power supplied from the power conversion unit 12 to the power line 4 and information about the power measured by the power measurement unit 8, so it can derive the load power of the power load device 15 (= output power + measured power). If the sign of the power measured by the power measurement unit 8 is positive, it means that the load power is greater than the output power of the fuel cell device 10, and if the sign of the power measured by the power measurement unit 8 is negative, it means that the output power of the fuel cell device 10 is greater than the load power.

[0041] The fuel cell device 10 is connected to a remote control 9, which is operated by users of facility 2 when they issue commands to the fuel cell device 10. Information about the output power and load power of the fuel cell device 10 is transmitted to the management device 20 via the remote control 9 and router 7. For example, information about the output power and load power of the fuel cell device 10 is transmitted to the management device 20 at predetermined intervals, such as every minute.

[0042] As described above, the control device 20 is configured to adjust the output power of each of the multiple fuel cell devices 10. The fuel cell devices 10 adjust their output power based on output adjustment commands, including output control commands and follow-up operation commands, from the control device 20.

[0043] An output control command is a command transmitted from the control device 20 to the fuel cell device 10, which determines the output power of the fuel cell device 10 when the control device 20 decides to perform constant-value operation. Therefore, when the fuel cell device 10 receives an output control command from the control device 20, it operates with the goal of supplying the output power determined based on the output control command during the controlled period covered by the output control command. As a result, the fuel cell device 10 performs constant-value operation, setting the output voltage to a predetermined value commanded by the control device 20.

[0044] A follow-up operation command is a command transmitted from the control device 20 to the fuel cell device 10, which has decided to perform follow-up operation. Therefore, when the fuel cell device 10 receives a follow-up operation command from the control device 20, it operates to supply output power corresponding to the load power of the power load device 15 in accordance with the follow-up operation command. As a result, the fuel cell device 10 performs follow-up operation, adjusting its output voltage to match the load power of the power load device 15 installed in the same facility 2. In follow-up operation, for example, the fuel cell control unit 13 adjusts the output power of the fuel cell device 10 so that the power measured by the power measurement unit 8 (i.e., the power supplied from the power system 3) is zero or close to zero, thereby operating it to match the load power of the power load device 15.

[0045] In this embodiment, the control device 20 adjusts the number of fuel cell devices 10 that will perform follow-up operation, which is the number of fuel cell devices 10 that will perform follow-up operation, and the number of fuel cell devices 10 that will perform constant-value operation, which is the number of fuel cell devices 10 that will perform constant-value operation, so that power is supplied from facility 2 to power grid 3. The control device 20 transmits the output control command described above to the fuel cell devices 10 that have been determined to perform constant-value operation, which determines the output power of the fuel cell device 10. The control device 20 also transmits the follow-up operation command described above to the fuel cell devices 10 that have been determined to perform follow-up operation.

[0046] In other words, a fuel cell device 10 that has been determined by the control device 20 to perform constant-value operation will operate to output the output power specified by the output control command. On the other hand, a fuel cell device 10 that has been determined by the control device 20 to perform follow-up operation will operate in a way that allows the output power to follow the load power of the power load device 15, as described above, by having the fuel cell control unit 13 adjust the output power of the fuel cell device 10 so that the power measured by the power measurement unit 8 (i.e., the power supplied from the power system 3) is zero or close to zero.

[0047] In this embodiment, as shown in Figure 3(A), the control device 20 repeatedly issues output adjustment commands, including output control commands and follow-up operation commands, every first hour. That is, the output power of the fuel cell device 10 performing constant-value operation is determined every first hour by the output adjustment commands from the control device 20, and the output power of the fuel cell device 10 performing follow-up operation is determined by local control at the facility 2 to follow the load power of the power load device 15.

[0048] The control device 20 increases the number of fixed operating units as the target reverse power flow amount that needs to be supplied from multiple facilities 2 to the power system 3 increases. For example, it is preferable for the control device 20 to store in advance the fuel cell devices 10 installed in multiple facilities 2 that are subject to adjustment, and also store the relationship between the target reverse power flow amount and the fixed operating unit in that case. In this case, once the target reverse power flow amount is determined, the control device 20 can determine the fixed operating unit based on the relationship between the target reverse power flow amount and the fixed operating unit that has been stored in advance.

[0049] Thus, the larger the target amount of reverse power flow electricity that needs to be supplied from multiple facilities 2 to the power system 3, the larger the number of fuel cell units 10 that perform constant-value operation, which adjusts their output power to a predetermined value commanded by the management device 20 so that power is supplied from facilities 2 to the power system 3. Therefore, it becomes possible to supply a sufficient amount of reverse power flow electricity to the power system 3 from the fuel cell units 10 performing constant-value operation. Conversely, the smaller the target amount of reverse power flow electricity that needs to be supplied from multiple facilities 2 to the power system 3, the smaller the number of fuel cell units 10 that perform constant-value operation. As a result, it becomes possible to reliably procure the required amount of reverse power flow electricity from multiple fuel cell units 10 according to the target amount of reverse power flow electricity.

[0050] Furthermore, the control device 20 determines, based on the predicted amount of reverse power flowable electricity that each of the multiple facilities 2 can supply to the power grid 3 in the future, and the error in the reverse power flowable electricity amount, to be the fuel cell device 10 among the multiple fuel cell devices 10 that has a small error in the reverse power flowable electricity amount and to be the fuel cell device 10 that will perform constant-value operation.

[0051] The amount of power that can be reverse-flowed is predicted by subtracting the predicted demand power from the upper limit output power, based on the past operating data of each of the multiple fuel cell devices 10. The operating data is sent from each of the fuel cell devices 10 to the control device 20 at predetermined intervals. The control device 20 predicts the amount of power that can be reverse-flowed based on the operating data for the same time period as the time period during which reverse-flow power is required due to supply and demand tightness. The predicted amount of power that can be reverse-flowed is adjusted to account for errors based on the operating data. That is, the greater the variation in the amount of power used based on past operating data, the larger the error is set, and the smaller the variation in the amount of power used, the smaller the error is set.

[0052] For example, consider four fuel cell devices 10: device A, device B, device C, and device D. The reverse power flow capacity and error for each device are shown below.

[0053] Equipment A: 200Wh±100Wh Equipment B: 400Wh±100Wh Equipment C: 350Wh±200Wh Equipment D:300Wh±200Wh Here, the value to the left of ± represents the amount of power that can be reverse-flowed, and the value to the right of ± represents the error.

[0054] If the target reverse power flow is 500 Wh, then the control device 20 will operate the fuel cell devices 10 that have small errors in their predicted reverse power flow capacity and whose reverse power flow capacity satisfies the target reverse power flow capacity (500 Wh), in constant-value operation mode. In this way, the control device 20 prioritizes the fuel cell devices 10 with small errors and determines which fuel cell devices 10 will operate in constant-value operation mode.

[0055] The amount of power that can be reverse-flowed is predicted at each facility 2. For example, a remote control 9 (an example of a "prediction device") installed at each facility 2 determines the surplus power derived by subtracting the current load power of the power load device 15 from the upper limit output power of the fuel cell device 10. Assuming that the determined surplus power is continuously generated, the remote control 9 determines the amount of power that can be reverse-flowed, which is predicted to be able to be supplied from facility 2 to the power system 3 in the future. The remote control 9 transmits the amount of power that can be reverse-flowed at facility 2 to the management device 20. In this case, the management device 20 is configured to receive information about the amount of power that can be reverse-flowed, which is predicted by each of the remote controls 9 of the multiple facilities 2.

[0056] Alternatively, the management device 20 may receive information from the remote control 9 of each facility 2 regarding the current load power of the power load device 15 of each facility 2, and, taking into account the upper limit output power of the fuel cell device 10 of each facility 2, determine the amount of reverse power that can be supplied from each facility 2 to the power system 3 in the future. In this case, the management device 20 is configured to predict the amount of reverse power that can be supplied based on the predicted load power of the power load device 15 and the output power of the fuel cell device 10, which are received from each of the multiple facilities 2.

[0057] Furthermore, in the unit adjustment process, the control device 20 may determine the number of units to operate at a constant value such that the total amount of reverse power that can be supplied in reverse at each of the facilities 2 where the fuel cell units 10 operating at a constant value are installed is by a set value greater than the target amount of reverse power that needs to be supplied from multiple facilities 2 to the power grid 3.

[0058] Specifically, for example, at a certain time or earlier, the control device 20 may set the number of follow-up fuel cell devices 10 performing follow-up operation to X units, and the number of constant-value fuel cell devices 10 performing constant-value operation, each supplying PkWh of reverse power flow to the power system 3 in A minutes, to Y units, and then transmit such an output control command. In this case, if the total amount of reverse power flow available at each of the facilities 2 where the constant-value fuel cell devices 10 are installed is (P × Y)kWh, and the target amount of reverse power flow that needs to be supplied to the power system 3 from multiple facilities 2 is POkWh, then the number of constant-value operating units is determined to be POkWh more than the set value (for example, a few kWh).

[0059] In the power management system 1, when the management device 20 issues an output control command or a follow-up operation command to each of the multiple fuel cell devices 10, each of the multiple fuel cell devices 10 is configured to check with the management device 20 at a predetermined first set time interval to see if there is an instruction for the fuel cell device 10. The first set time interval is a time shorter than the first hour, as shown in Figure 3(B). The instruction for the fuel cell device 10 is an output adjustment command, including an output control command or a follow-up operation command, and specifically refers to an instruction to switch from constant-value operation and follow-up operation to the other. Each of the multiple fuel cell devices 10 continuously checks with the management device 20 at a first set time interval shorter than the first hour to see if there is an instruction to switch from the currently operating constant-value operation and follow-up operation to the other.

[0060] Furthermore, the output adjustment command sent every hour includes a command to each fuel cell unit 10 to confirm instructions to the control device 20 at a second set time interval, which is shorter than the first set time interval, until a predetermined time has elapsed since receiving the output adjustment command (see Figure 3(C)). "Until a predetermined time has elapsed since receiving the output adjustment command" is a time shorter than the first hour from the time an output adjustment command is received at a predetermined timing until the next output adjustment command is received, and is shown as the second hour in Figure 3(C). Therefore, each fuel cell unit 10 confirms instructions to the control device 20 at a second set time interval, until a second hour, which is shorter than the first hour, has elapsed since receiving the output adjustment command. In other words, each fuel cell unit 10 confirms instructions to the control device 20 more frequently than when it confirms instructions at a first set time interval, until a second hour has elapsed since receiving the output adjustment command. After the second hour has elapsed, the above-mentioned confirmation of instructions is performed at a first set time interval until the first hour has elapsed since receiving the previous output adjustment command.

[0061] This makes it possible to quickly adjust the number of follow-up units or fixed-value units to match the amount of power supplied from facility 2 to power system 3, even if there is an error in the amount of reverse power flowable electricity predicted by the management device 20 and it is necessary to adjust the amount of power supplied, such as the number of follow-up units or fixed-value units, to match the amount of power supplied from facility 2 to power system 3 to the target amount of reverse power flowable electricity.

[0062] As described above, the control device 20 has an error in the amount of power that can be reverse-flowed, and if this error is large, the amount of power supplied from facility 2 to power system 3 may be insufficient. Therefore, in this embodiment, the control device 20 is configured to have each of the multiple fuel cell devices 10 confirm instructions to the control device 20 at a third setting time that is shorter than the first setting time, when the error in the amount of power that can be reverse-flowed is greater than a preset value. Since the third setting time is shorter than the first setting time, each of the fuel cell devices 10 confirms instructions to the control device 20 more frequently than when it confirms instructions to the control device 20 at a first setting time (see Figure 3(C)). The third setting time may be the same as the second setting time, shorter than the second setting time, or longer than the second setting time.

[0063] As described above, assuming that the reverse power flow capacity and error of equipment AD have been calculated, we will assume that equipment A (200Wh) and equipment B (400Wh) are being operated at a constant value, as their reverse power flow capacity satisfies the target reverse power flow capacity (500Wh).

[0064] In this case, since the actual reverse power flow differs from the target value, the control device 20 adjusts the number of fixed-value operating units and the number of follow-up operating units multiple times. Therefore, as described above, by increasing the frequency of confirmation communication from the multiple fuel cell devices 10 to the control device 20 (for example, increasing the communication frequency from once every 15 minutes to once every 5 minutes), it becomes possible to quickly reflect instructions from the control device 20 to each of the multiple fuel cell devices 10. On the other hand, when there is no need to adjust the number of fixed-value operating units and the number of follow-up operating units, the communication frequency of confirmation from each of the multiple fuel cell devices 10 to the control device 20 is not increased (for example, the communication frequency is once every 15 minutes), so it is possible to suppress the increase in the amount of communication.

[0065] Next, the processing of the power management system 1 will be explained using the flowchart in Figure 4. In the power management system 1, processing is suspended until a supply command is received from the aggregation coordinator 30 (Step #1: No). When the management device 20 receives a supply command from the aggregation coordinator 30 (detects a tight power supply and demand) (Step #1: Yes), it calculates the control period and the target reverse power flow (Step #2). Then, the management device 20 selects the fuel cell device 10 from among the multiple fuel cell devices 10 to perform reverse power flow (Step #3).

[0066] When the controlled period is reached (Step #4: Yes), the control device 20 transmits an output adjustment command, including an output control command and a follow-up operation command, to the fuel cell device 10. As a result, the fuel cell device 10, which has received the output control command as an output adjustment command, starts reverse power flow (Step #5).

[0067] In this case, since an output adjustment command has been received (Step #6: Yes), the fuel cell unit 10 increases the frequency of communication with the control device 20 to confirm the instruction (Step #7). The fuel cell unit 10 operates in accordance with the output adjustment command (Step #8). The fuel cell unit 10 confirms the instruction with the control device 20 at this communication frequency until a predetermined time has elapsed (Step #9: No). Once the predetermined time has elapsed (Step #9: Yes), the fuel cell unit 10 returns the communication frequency to its original level (Step #10).

[0068] If the communication frequency is restored to its original value, the process terminates when the controlled period ends (Step #11: Yes). If the controlled period has not ended (Step #11: No), the process returns to Step #6 and continues.

[0069] If the fuel cell device 10 does not receive an output adjustment command in step #6 (step #6: No), processing continues from step #11 at the same communication frequency. The power management system 1 processes according to this flow.

[0070] [Other Embodiments] In the above embodiment, the management device 20 was described as prioritizing the fuel cell device 10 with the smallest error in the reverse power flow capacity among the multiple fuel cell devices 10, based on the predicted amount of reverse power flow capacity that each of the multiple facilities 2 can supply to the power grid 3 in the future, and the error in said reverse power flow capacity, to determine which fuel cell device 10 will perform constant-value operation. However, the management device 20 can also, for example, prioritize the fuel cell device 10 with a large reverse power flow capacity to determine which fuel cell device 10 will perform constant-value operation.

[0071] In the above embodiment, facility 2 was described as being equipped with a remote control 9 that predicts the amount of power that can be reverse-flowed. However, the prediction of the amount of power that can be reverse-flowed may be performed by the management device 20. Furthermore, the prediction device may be a device different from the remote control 9.

[0072] In the above embodiment, the management device 20 was described as being configured to predict the amount of power that can be reverse-flowed based on the predicted load power of the power load device 15 and the output power of the fuel cell device 10, which are received from each of the multiple facilities 2. However, the management device 20 may also be configured to predict the amount of power that can be reverse-flowed by taking into account other parameters (e.g., fuel consumption of the fuel cell device 10) in addition to the predicted load power of the power load device 15 and the output power of the fuel cell device 10.

[0073] In the above embodiment, the control device 20 was described as causing each of the multiple fuel cell devices 10 to confirm its instructions at a third set time interval shorter than the first set time, if the error in the amount of power that can be reverse-flowed is greater than a preset value. However, even if the error in the amount of power that can be reverse-flowed is greater than a preset value, the control device 20 does not need to cause each of the multiple fuel cell devices 10 to confirm its instructions at a third set time interval shorter than the first set time.

[0074] In the above embodiment, the management device 20 was described as determining the number of fixed-value operating units such that the total amount of reverse power flowable at each of the facilities 2 where the fuel cell devices 10 performing fixed-value operation are installed is greater than the target reverse power flow amount by a set value. However, the management device 20 may also determine the number of fixed-value operating units such that the total amount of reverse power flowable at each of the facilities 2 where the fuel cell devices 10 performing fixed-value operation are installed is equal to the target reverse power flow amount.

[0075] In the above embodiment, the control device 20 was described as repeatedly issuing output adjustment commands. However, the control device 20 can also be configured to issue output adjustment commands only once.

[0076] In the above embodiment, the power supply device used in the power management system 1 was described as a fuel cell device 10. However, the power supply device may be, for example, a generator driven by an internal combustion engine.

[0077] Furthermore, the configurations disclosed in each of the embodiments described above can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. Regarding other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate, without departing from the spirit of this disclosure. [Industrial applicability]

[0078] The present invention can be used in power management systems and fuel cell devices used in power management systems. [Explanation of Symbols]

[0079] 1: Power Management System 2: Facilities 3: Power system 7: Remote control (prediction device) 10: Fuel cell device (power supply device) 11:Fuel cell part (power supply part) 15: Electrical load devices

Claims

1. A power management system comprising power supply units installed in each of multiple facilities, and a management device capable of communicating with the multiple power supply units from a remote location outside the facilities, The aforementioned power supply unit includes a power supply unit connected to a power grid and is configured to adjust the output power between an upper limit output power and a lower limit output power. The power load device installed in the facility is configured to receive power from at least one of the power supply device and the power system installed in the facility. The management device adjusts the number of power supply units that perform follow operation, which is the number of power supply units that perform follow operation, in which the output power is adjusted to match the load power of the power load devices installed in the same facility, and the number of power supply units that perform constant operation, which is the number of power supply units that perform constant operation, in which the output power is adjusted to a predetermined value commanded by the management device so that power is supplied from the facility to the power system. The management device then issues an output adjustment command that includes an output control command for the power supply units that have been decided to perform constant operation, which determines the output power of the power supply units, and a follow operation command for the power supply units that have been decided to perform follow operation, which causes the power supply units to perform follow operation. Each of the multiple power supply units is configured to check whether or not there is an instruction for the power supply unit at predetermined first set time intervals. The output adjustment command includes a power management system that instructs each of the power supply units to confirm the instruction to the management device at a second set time interval shorter than the first set time interval, until a predetermined time has elapsed since receiving the output adjustment command.

2. The power management system according to claim 1, wherein the management device determines, based on the amount of reverse power flowable electricity that is predicted to be able to be supplied from each of the multiple facilities to the power grid in the future, and the error in the amount of reverse power flowable electricity, to be the power supply unit that performs the constant value operation, prioritizing the power supply unit with the smallest error in the amount of reverse power flowable electricity among the multiple power supply units.

3. The facility is equipped with a prediction device for predicting the amount of power that can be reverse-flowed, The power management system according to claim 2, wherein the management device is configured to receive information about the amount of reverse power flow possible predicted by the prediction device of each of the multiple facilities.

4. The power management system according to claim 2, wherein the management device is configured to predict the amount of power that can be reverse-flowed based on the predicted load power of the power load device and the output power of the power supply device, which are predicted to be received from each of the multiple facilities in the future.

5. The power management system according to claim 2, wherein if the error is greater than a preset value, the management device causes each of the multiple power supply units to confirm the instruction to the management device at intervals of a third set time that is shorter than the first set time.

6. The power management system according to any one of claims 2 to 5, wherein the management device determines the number of fixed-value operating units in the adjustment of the number of fixed-value operating units such that the total amount of reverse power flow possible at each of the facilities where the power supply units performing the fixed-value operation are installed is greater than the target reverse power flow amount by a set value.

7. The power management system according to any one of claims 2 to 5, wherein the control device repeatedly performs the output adjustment command.

8. A fuel cell device having the functions of a power supply device used in a power management system according to any one of claims 2 to 5, wherein the power supply unit comprises a fuel cell unit.

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